KR100197823B1 - Correct lens assembly and collimator assembly using optical device - Google Patents

Abstract

The present invention relates to an assembly of an improved collimation with two isolated light paths. Each of the optical paths passes through the corrective lens assembly, which is dispersed while being aligned with one of the two alternative lens assemblies. Each correction lens assembly is structured in such a way that light passing through the correction lens assembly is selectively refracted to neutralize and reduce the axial chromatic aberration generated in the alternative lens assemblies.

Description

Assembly of corrective lens assembly and collimation for use in optical devices

1 is a schematic diagram of lenses of a night vision spectacle device according to the prior art, showing a state in which on-axis field light rays pass through the optical apparatus for ease of explanation.

FIG. 2 is a schematic view showing a cross section of the lenses according to the prior art shown in FIG. 1 showing temporary off-axis field light rays passing through the optical element shown.

3 is a schematic view showing a preferred embodiment of the lens assembly of the present invention incorporated into a night vision spectacle device.

FIG. 4 is a schematic diagram of the lens assembly shown in FIG. 4 showing axial, non-axial transient light rays passing through the optical elements shown.

5 is a side view showing the structure and arrangement of the collimating assembly of the present invention, showing only one of the dually distributed correction lens arrangements.

6 (a) is a schematic diagram showing one alternative lens assembly of the night vision eyeglasses shown in FIGS. 1 and 2;

FIG. 6 (b) is a graph showing axial chromatic aberration generated by an alternative lens assembly according to the prior art of FIG. 6 (a).

7 is a side view showing one embodiment of the correcting lens arrangement of the present invention.

8 (a) is a schematic diagram showing the lenses of the corrective lens arrangement according to the invention of FIG. 7 with respect to the alternative lens assembly according to the prior art of FIG. 6 (a).

8 (b) is a graph showing axial chromatic aberration generated by the lenses of FIG. 8 (a).

* Explanation of symbols for main parts of the drawings

30 assembly of collimation 32 connection lens

34: correction lens assembly 36,38: correction lens array

40: biconvex lens 42: meniscus lens

44,46 bi-lens 50,52 aspherical lens

62: biconvex lens 64: biconvex lens

The present invention creates two unique optical paths by re-imaging an infinite conjugate of a single image source for binocular viewing of an image through a separate alternative lens. To an assembly of collimators. In addition, the light rays passing from the assembly of collimation to the alternative lenses are selectively altered to neutralize and reduce the chromatic aberrations produced by the optical elements of each alternative lens. Many optical devices, such as certain microscopes, telescopes, and night vision devices, are binocular but have only one objective lens arrangement. When a single source is viewed in binocular vision, the light beam from the image can be split into individual corresponding optical outputs that can be viewed simultaneously. Traditionally, the splitting of a single image source into two corresponding binocular images is done using a collimating lens assembly. Traditionally, collimation is an optical device for generating parallel rays. The basic form consists of a collecting lens, and a small light source is positioned at one focal point of the establishing lens. The light source is usually a pinhole or narrow slit, and light is emitted from the invasion or void. Light rays diffused from the focal point are emitted in parallel beams from the objective lens, according to the definition of focus. The void or other light source observed through collimation appears to be placed at an infinite distance. The collimation lens assembly thus reimages the light source image in the infinite void. Thus, the collimated light beam from the reimaged light source image is split equally without distortion or parallax and the respective alternative lens assemblies are also directed for observation. The alternative lens assemblies are shaped and positioned to receive light beams collimated from the lens assembly of the collimation and sized to divide the light beam portions contained within the collimation exit pupil.

Traditional collimating lens assemblies are formed from lenses that are symmetrically constructed about the longitudinal axis of the assembly. By this formation, the optical axes of the lenses in the collimating lens assembly are linearly aligned and rotationally symmetric about the longitudinal axis. For lens arrangements that are linearly aligned and rotationally symmetric, it is well known that the best optical performance is obtained on light rays traveling along the light side of the lenses. Such an optical path is defined as an on-axis passageway of the lens assembly. The optical performance of the lens assembly is reduced for light rays that are off-axis within the field of view. As light travels off-axis toward the edge of the field of view, optical performance is significantly worse. Since many traditional collimating lens assemblies have a common optical axis for all constituent lenses, the collimating lens assembly has only one on-axis position centered in a single optical path. Since the lens assemblies of the traditional collimation have only one central pupil position, when the light is split for binocular observation, the image is split evenly on both sides of the center of the pupil position. It is impossible to direct all the light passing through the center of the pupil position to both alternative lenses simultaneously. When the image produced by the collimating lens assembly is segmented, therefore, mostly diffuse or eccentric pupil rays are directed to the alternative lens, and the optical performance of the collimating lens assembly is also present in the alternative lens induced chromatic aberration on the binocular side. Is sacrificed by the balance of performance.

A typical prior art optical device for dividing light for binocular observation is shown in FIG. Other optics using split light from collimated lens assemblies in dispersed pupil and / or non-axial positions are disclosed in US Pat. No. 3,781,560 to DeBurgh et al., US Patent No. 4,266,129 to Versteeg et al., Rohers. 4,392,710 and US Pat. No. 4,463,252 to Brennan et al. All of these patents relate to night vision optics.

In addition to the off-axis and / or distributed use of collimating lenses, single source optical systems used for binocular observation have other drawbacks. The most important of these defects is that chromatic aberration occurs in the observed image.

It is well known that chromatic aberration occurs due to the passage of light through the optical lenses. The collimating lens assemblies include many different component lenses, so many collimating lens assemblies according to the prior art reduce chromatic aberration by changing the material, shape and magnification of each component lens to compensate for chromatic aberration. It is structured to be. Similarly, many optical assemblies made of lenses for enlargement or reduction will compensate for a certain amount of chromatic aberration by changing the component lens structure. Prior art designs in which the lens arrangement is designed to compensate for specific chromatic aberrations are described in the following United States patents.

5,011,272 to NAkayama et al. 4,397,520 to Neil

Kikuchi 4,963,010 Muchel 4,365,871

Cooper 4,871,219 Baker 4,171,872

4,641,927 to Prescott et al. 3,827,785 to Matsusbita et al.

4,435,041 to Torok et al. 3,635,295 to Matsumura et al.

Neil 4,411,485 Baker 3,604,786

However, the lenses forming the collimating lens assembly are not the only optical elements that cause chromatic aberration. In binocular observation, two alternative lens assemblies are used, one for each eye. The alternative lens assemblies may have a simple lens arrangement or lenses that magnify the image to invert an inverted image for normal viewing. Often, chromatic aberrations of alternative lenses are not fully corrected, resulting in poor quality of the observed image. Axial chromatic aberration in the prior art has been ignored as insignificant or difficult to correct with cost effective lenses. In classical chromatic aberration theory, there was a conventional chromatic aberration limitation called lens axial chromatic aberration or axial color in performance of lens design. This is defined as the extent to which red, green and blue rays, or other long, nominal and short wavelengths, are connected to other points along the optical axis. In applications such as night vision lenses, the observed image may be present within a more limited wavelength range than blue to red light, but will produce an alternative chromatic aberration that may cause a significant degradation in the observed image quality. It becomes possible.

It is therefore a primary object of the present invention to provide an optical assembly in which a single image source is directed to two eyepieces for binocular observation such that each alternative lens receives light from the dispersive portion of the exit pupil of the collimation assembly. Is in.

It is another object of the present invention to provide an assembly of collimation for correcting an image to compensate for and reduce axial chromatic aberration which undesirably distorts the image due to the optical elements of the alternative lenses in which the image is observed.

The present invention relates to an assembly of collimation for reimaging a single circle image with infinite conjugate so that the image can be observed in binocular vision. The present invention provides two unique light paths for each alternative lens assembly, including a splice lens element in combination with the injected correcting lens assembly. Each of the optical paths is each aligned with one of the two alternative lens assemblies used for binocular observation. Additionally, the dual correction lens assembly is positioned in such a way that the primary light waves traveling along each optical path in the collimation assembly are passed through the lenses of the dual correction lens assembly at a central position with respect to the symmetry width of the alternative lens assembly. do.

The dual corrective lens assembly includes two corrective lens arrangements oriented in close proximity to one another. Each corrective lens assembly is formed to be afocal to light in the middle region of the spectral range used. The correction lenses are not connected indefinitely to the wavelengths of light above and below the middle zone. Correction lens arrangements refract light in a manner that compensates for axial chromatic aberration produced by the optical components of the alternative lens assemblies. By correcting light for axial chromatic aberration, the chromatic aberration is reduced throughout the entire field of view.

Due to the correction of the axial chromatic aberration associated with the central use of the corrected lens arrangements, a high quality observation image with less distortion than the prior art is provided.

Hereinafter, the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, there is shown schematically a lens for a model AN / PVS-7B night vision spectacles marketed by the assignee of the present invention, International Telephone and Teregraph, Inc. The illustrated night vision device 10 operates by receiving visible infrared or near infrared light through an objective lens assembly 12 and connecting the light beam onto an image intensifier tube assembly 14. do. The image enhancer tube 14 converts the input beam into a visible image, which can be observed by viewing through the alternative lens assemblies 16, 18. In night vision, the device provides an image using a light wavelength with a relatively narrow spectral range.

The illustrated night vision device 10 has only one objective lens assembly 12, but the resulting image is viewed through two alternative lens assemblies 16, 18 for the binocular of the observer. For this reason, it is necessary to reimage the output image of the image intensifier 14 in such a manner that two output images are generated, and the binocular vision is used.

In the prior system shown, two output images are generated by the use of the assembly of collimation 20 comprising a biscattering mirror 22. The output surface 24 of the image enhancer assembly 14 of the lenses of the collimating assembly 20 is reimaged to infinity to impart infinite conjugated objects to the alternative lens assemblies 16, 18. By reimaging the output surface 24 of the image enhancer tube 14 to infinite conjugation, the collimated light exiting the assembly of the collimator is captured by the bidispersion mirror 22 (ultimately for each eye). Can be divided into four images. The double dispersion mirror 22 reflects light from only half of the lenses of the collimation assembly 20 (lens output pupil of the collimation) to each alternative lens assembly 16, 18. Since the output surface 24 of the image augment tube 14 is reimaged to infinity, the binocular vision is achieved by simply splitting the collimated light and directing the light to the respective alternative lens assemblies 16, 18. It is easily possible. In order to avoid vignetting of light from the periphery of the augmented tube face, it is desirable to position the double dispersion mirror 22 close to the output surface of the collimating lens (output collimation of the collimation) and the alternative lens assembly pupil (corresponding pupil). It is necessary. Therefore, the axial error of light is reduced by placing each of the alternative lens assemblies 16, 18 close to the bi-dispersion mirror 22. The mirror should be larger or the same size as the alternative lens pupil.

In the embodiment according to the prior art shown in FIG. 1, the rays 28 are shown as entering the objective lens assembly 12 parallel to the longitudinal axis of the system. The incoming rays of light generate an output image from the center of the image augmentation tube assembly 14, which is co-axial with the light side of the collimating assembly 20 (ON-AXIS). However, in practical use, temporary light is introduced into the objective lens assembly 12 at an angle that varies with the longitudinal axis of the system. Light angled as described above generates OFF-XIS images from the image enhancer tube 14.

Referring to FIG. 2, there is shown asymmetric light directed through one of the collimating assemblies 20 and directed to one alternative lens assembly 18, which is generated by the image enhancer tube assembly 14.

The assembly of collimation 20 of the device according to the prior art has respective optical lenses which are symmetrically formed around a common longitudinal axis. Thus, each lens element in the collimating assembly 20 occupies a common optical axis. It is well known in the optics industry that the optical performance of the system in this symmetrical optical shape is such that the system is best along the on-axis optical path. The optical performance is gradually reduced as non-axial light is moved toward the peripheral edges of the field of view. As shown in FIGS. 1 and 2, the assembly of collimation 20 is not used for axial use. The assembly of collimation 20 is used to form two collimated images through the biscattering mirror 22. The light path for each image is passed through the collimating lens assembly 20 in a dispersed position. In fact, the center of each reflective surface of the biscattering mirror 22 and the light paths of each of the alternative lens assemblies 16, 18 are not all aligned in a dispersed position with respect to the exit cavity of the collimating lens assembly 20. do. The light path of each of the alternative lens assemblies 16, 18 is aligned on the assembly of collimation 20 in an intermediate, distributed position between the axial and peripheral edges of the exit cavity of the collimation assembly 20.

The present invention can be used in many other applications where a single image source is viewed in binocular vision or chromatic aberration is created by alternative lens assemblies. However, the present invention is particularly suitable for use in connection with night vision devices. Accordingly, the present invention is particularly suitable for use in connection with night vision devices. Accordingly, the present invention is described in connection with improving the prior art model AN / PVS-7B night vision glasses described above.

Referring to FIG. 3, the assembly of the collimation 30 in accordance with the present invention is shown integrated into a model AN / PVS-7B night vision eyeglass system. The assembly of collimation 30 according to the invention comprises a connecting lens 32, a dual dispersion correction lens assembly 34 and a double dispersion mirror 22. The dually distributed corrective lens assembly 34 is preferably constructed with two unique corrective lens arrangements 36, 38 in close proximity to one another. Each corrective lens arrangement 36, 38 is positioned such that the axial position of each corrective lens assembly 36, 38 is aligned with the central optical path of the two alternative lens assemblies 16, 18, respectively. The double scattering correction lens assembly 34 creates two separate light paths for light traversing the assembly 30 of the collimation.

In FIG. 4, the corrective lens assembly 30 according to the present invention is shown in a state of connecting both axial and non-axial light generated by the steel pipe assembly 14 in the image. As shown, axial and non-axial light from the entire output surface 24 of the image enhancer tube assembly 14 is directed into the respective corrective lens arrangements 36 and 38. Since the corrective lens arrangements 36, 38 are centrally located within the pupils of the alternative lens assemblies 16, 18, a large amount of ambient light from the image enhancer tube 14 does not cause significant axial error. You will be connected without it. The corrective lens arrangements 36, 38 are formed to be infinitely connected compared to the contact lens 32, so telecentricity of the optical path as the image light is passed into the respective alternative lens assemblies 16, 18. ) Will be preserved.

A specific structure according to a preferred embodiment of the connecting lenses 32 of the collimating assembly 30 according to the present invention will be described with reference to the following table and FIG. 5. As shown, the connecting lenses 32 are composed of five isolated lens elements. The lens elements include a biconvex lens 40, a meniscus lens 42, a first dual lens 44, a second dual lens 46 and a plano-convex lens 48. do. The optical materials constituting each lens element are as follows:

Referring to FIG. 5, the physical parameters of each lens element are explained together with the overall arrangement of the contact lens 32:

Referring to FIG. 6A, there is shown a single alternative lens assembly 18 according to the prior art used in one shape of PVS-7B glasses. The alternative lens assembly comprises two identically shaped aspheric lenses 50 and 52 of the same material, such as cast plastic. The alternative lens assembly 18 receives uncorrected light reflected from the biscattering mirror 22. Light passing through the first aspherical lens 50 is reflected from the fold mirror 54 and reflected through the second aspherical lens 52. The image is then observed by the viewer through the protective glass 55. In a preferred embodiment, the non-spherical lenses 50, 52 are used to invert the image reflected from the biscattering mirror 22 and arranged with respect to each other so as not to have a particular optical power. The aspherical lenses 50 and 52 are preferably constructed of inexpensive material such as plastic. Such lenses are lighter and less expensive than other possible lens types, thus increasing the demand for such structures. However, molding the same non-spherical lenses from similar materials has drawbacks. The most important of the phase defects is that it becomes impossible to eliminate axial chromatic aberration. The same lenses made of one material have only one dispersion characteristic. For this reason, the non-spherical lenses 50 and 52 have no ability to balance each other's chromatic aberration. Thus, alternative lenses using non-spherical lenses 50 and 52 will cause assemblies to chromatic distortion of the optical system.

Light passing through the alternative lens assembly 18 includes all wavelengths in the desired spectral range. It is well known in the art that a separate focal point will be formed for each wavelength passing through the biconvex lens. To illustrate this phenomenon, the wavelength of light in the middle region of a given spectral range is considered as the nominal wavelength. Therefore, the nominal wavelength of light is connected at a single nominal focal point. The nominal focus is used as a reference point for measuring the distortion of other wavelengths of light located above or below the nominal wavelength of light. As shown on the graph, the distance of the junction of the non-nominal wavelength of light can be plotted against the nominal focal point on the X-Y grating through the field of view. Thus, the focus of the nominal light wavelength can be compared with the nominal focus by the X and Y coordinate system.

Referring to FIG. 6B, there is shown a graph showing varying chromatic aberration of the alternative lens assembly 18 (shown in FIG. 6A) according to the prior art. Two graphs are shown for light with a nominal wavelength of 556.3 nm, the two graphs having a nominal wavelengths of 515, 3 nm and 604.5 nm. The first graph shows the Y-pan of chromatic aberration. The Y-pan represents the transverse position of the focal points for various wavelengths across the pupil diameter in the Y axis. Similarly, the second graph shows the transverse position of the focal points for various wavelengths over the pupil diameter in the X axis. As can be clearly seen, wavelengths above or below the nominal wavelength have significantly different foci, and thus can cause sharp axial chromatic aberration when observed by the observer.

As noted above, the dually distributed corrective lens assembly 32 is formed as part of the collimating assembly 30 of the present invention to create two separate light paths for each eye of the observer (see FIG. 3). do. The dually distributed correction lens assembly 34 is composed of two axially adjacent correction lens arrangements 36, 38. Correction lens arrangements 36, 38 selectively refract light passing through the arrangements and neutralize axial chromatic aberration generated in the light as light passes through the alternative lens assemblies 16, 18. Are rescued.

7 shows a yellow cross-sectional side view of one corrective lens arrangement 36. The corrective lens arrangement 36 is a dual lens and is molded to have zero light power for monochromatic light in the middle region of the required spectral range. In such a structure, the wavelengths of the middle region of the required spectral range enter and exit the corrective lens arrangement 36 along parallel optical paths. However, wavelengths shorter or longer than the mid-zone wavelength are refracted to neutralize axial chromatic aberration that may occur in alternative lens assemblies (see also FIG. 6B). For example, when the light penetrating the corrective lens array 36 is visible light, the corrected lens array 36 has zero light power, compared to the focus 32, for light near the green wavelength, Is refracted towards the red and blue wavelengths.

The corrective lens arrangement 36 consists of a specific number of optical elements which are combined to have the above characteristics. However, according to a preferred embodiment, the arrangement is a bilens, consisting of a biconvex lens 62 bonded to a biconcave lens 64. Physical elements for the biconvex lens 62 and the biconcave lens 64 are described below with reference to FIG. 7;

The biconvex lens 62 and the biconvex lens 64 are joined on the surface R10 by optical cement or other means known in the art. The point of the corrective lens arrangement closest to the end lens 48 of the connecting lenses 32 is isolated by a space S5 of 2.28 nm.

FIG. 8A shows the alternative lens assembly 18 of FIG. 6A for receiving chromatic aberration adjusted light through the corrective lens arrangement 36. As already explained, the corrective lens arrangement 36 is infinitely connected to wavelengths in the middle region of a given spectral range.

However, the wavelengths above and below the midzone wavelengths are refracted to compensate for the chromatic aberration that will be generated within the alternative lens assembly 18. Referring to FIG. 8B, Y-pan and X-pan graphs of corrected light through the alternative lens assembly 918 are shown for the three wavelengths previously used in FIG. 6B. When comparing the corrected wavelength of FIG. 8B with the uncorrected wavelength of FIG. 6B, it can be easily seen that the amount of axial chromatic aberration is reduced.

Referring again to FIGS. 3 and 4, the two collimating lens arrangements 36, 38, in which the assembly of the collimation of the invention 30 is axially located in the dually distributed correcting lens assembly 34. It can be seen that The two corrective lens arrangements 36, 38 create two separate distributed light paths in the collimation assembly 30 and are dispersed in the pupil of the alternative lens assemblies 16, 18 for axial chromatic aberration. It serves to compensate for light. Although the dual optical path of the present invention improves off-axis optical performance over the prior art, it is clear that it does not completely eliminate non-axis optical chromatic aberration. Non-axis light causes axial chromatic aberration at all non-axis locations in the lens assembly. However, when the lens assembly is telescopic optical (ie, when the main rays of light are parallel or nearly parallel to the optical axis of the assembly), the change in the axial chromatic aberration effect of the axial color is minimized and the axial color is constant throughout the field of view. . In the illustrated embodiment, the corrective lens arrangements 36, 38 are located behind the collimation assembly 30. Corrective lens arrangements therefore receive light from the telescope optical system. Since there is no off-axis light that causes lateral chromatic aberration, there is little lateral disturbance in axial chromatic differences. Thus, the corrective lens arrangements 36, 38 positioned near the pupil of the alternative lens assemblies 16, 18 are equally axial chromatic aberration throughout the entire field of view when viewed through the alternative lens assemblies 16, 18. Will be corrected.

As noted above, the present invention is not limited to night vision devices, and may be used in certain applications where a single image source is viewed binocularly and chromatic aberration is present in the alternative lens assembly. However, the present invention can be used to improve certain single source / dual optical output systems such as simultaneous observation and photography. However, it will be readily apparent to one of ordinary skill in the art that the present invention may be used to improve certain single source / dual optical output systems such as simultaneous observation and photography. The present invention can also be used in laser systems where one optical path is used to emit a laser and the other optical path is used to observe the effects of the laser in real time. Such laser applications will include surgical and fabrication processes such as cutting and welding.

The illustrated and described embodiments are exemplary only, and the present invention may be variously modified and modified without departing from the spirit and scope of the present invention. In particular, the present invention encompasses the overall performance characteristics of the optical elements described, and the particular single optical element described above may be replaced with a modified optical assembly as long as the optical performance is maintained as described above. All such changes and modifications are intended to be included within the scope of this invention as set forth in the following claims.

Claims (12)

A correction lens assembly for reducing the axial chromatic aberration, which is used in an optical device having an optical arrangement that creates axial chromatic aberration in light of a predetermined spectral range, comprising: a plurality of lens elements having different refractive properties and given sizes, The lens elements are arranged along the optical axis with infinite connection to the wavelengths of light in the middle region of the spectral range such that light in the region entering the lens elements is emitted from the lens element in a parallel direction. Wavelengths of light in the intermediate zone and other zones comprise a plurality of lens elements refracted in a manner to neutralize the axial sagchacha. The lens assembly of claim 1, wherein the lens elements do not significantly affect the magnification of the optical arrangement. 3. The corrective lens assembly of claim 2, wherein said lens elements are bilenses. 4. The corrective lens assembly of claim 3, wherein the double lens is formed of a biconvex lens and a biconvex lens coupled at an interface. 5. The correction according to claim 4, wherein the amphipathic lens has a refractive index of 1.85, a radius of curvature of 28.12 mm at the interface, a radius of curvature of 25.90 mm at a position opposite the interface and a minimum lens thickness of 1.24 mm. Lens assembly. 6. The correction according to claim 5, wherein the biconvex lens has a refractive index of 1.88, a radius of curvature of 28.12 mm at the interface, a radius of curvature of 29.95 mm and a minimum lens thickness of 2.92 mm at the surface opposite the interface. Lens assembly. A correction lens assembly for use in said optics that receives light parallel to the optical axis of the optics from a predetermined spectral range to reduce axial chromatic aberration, comprising: lens elements located in the pupil of said optics into which light enters; The lens elements are infinitely connected to wavelengths of light in the middle region of the spectral range, and light having different wavelengths from the light in the middle region is refracted to the axial direction. And a plurality of lens elements for reducing chromatic aberration. 8. The corrective lens assembly of claim 7, wherein the lens elements do not significantly change the light power of the optics. 8. The corrective lens assembly of claim 7, wherein the axial chromatic aberration is created by two or more non-spherical lenses having similar refractive indices. 10. The corrective lens assembly of claim 9, wherein the optics is an alternative lens assembly through which the image is viewed. 11. The corrective lens assembly of claim 10, wherein said lens elements are bilenses. 12. The corrective lens assembly of claim 11, wherein the bilens are formed of both concave and convex lenses coupled at an interface.